In a sense amp using ΔΣmodulation, a current of a bit line is quantized when data is read, the quantized value is counted, and data to be held by a memory cell is recognized. When the data is read, a counter uses a digital counter to read the data.
Thus, an enormous region is occupied by a circuit area of the counter in the sense amp. The circuit area of the digital counter becomes enormous as the memory cell holds multi-level data.